Police in New York City have removed demonstrators who had occupied a building at Columbia University to protest Israel's attacks on the Gaza Strip.

The university on Monday set a deadline for the students, who had set up tents, to leave. It threatened to suspend them if they did not comply.

The notice enraged some protesters, who occupied a building on campus the following day.

On Tuesday evening, local time, police officers stormed the building and forcibly removed the demonstrators.

New York Police Department officials told reporters prior to the operation that outside agitators were trying to hijack peaceful demonstrations to heighten tensions.

They said they were ready to cooperate if there was a request from the university.

Police arrested more than 100 demonstrators at Columbia on April 18. This sparked protests at other universities across the US.